Wash and boil the potatoes in the pressure cooker. Once it is cool, peel it and mash it. Also keep all other ingredients ready and handy.
Take a frying pan, add oil and mustard seeds. Once the mustard starts spluttering add jeera, urad dal, chana dal and cashews one by one. Saute it for a while. When the urad dal turns brown add slit green chilli, finely chopped ginger and curry leaves. Saute it for 5 seconds.
Add in turmeric powder and asafoetida and saute it for a while. Next add in chopped onions and fry till the onions turn soft.
Now add in mashed potato and mix for a while, Once it is mixed add in salt and chopped coriander leaves and mix it again. If you are planning to use this as an accompaniment with dosa, then swith off the stove and stop at this stage.
To use this as an accompaniment with poori add 1/4 cup of water, mix it for a minute and then switch off the stove. For chapathi you can either serve the dry version or the gravy version.